Exhaust system



1965 c. P. FOWLER ETAL 3,167,060

EXHAUST SYSTEM Filed Sept. 14, 1962 2 Sheets-Sheet 1 VI d/Fcr J da 67's E- BY fwo Jan. 26, 1965 c. P. FOWLER ETAL 3,

EXHAUST SYSTEM 2 Sheets-Sheet 2 Filed Sept. 14, 1962 United States Patent 0 3,167,969 EXHAUST SYfilEM Charles P. Fowler, Jackson, Mich and Walter H. llowers,

Racine, Wis., assignors to Wall-:er Manufacturing Company, Racine, Win, a corporation of Delaware Filed Sept. 14, 1962, Ser. No. 223,654 36 Claims. (Cl. l23lll9) This invention relates to crankcase ventilation systems for internal combustion engines and, more particularly, to crankcase ventilation systems that recirculate the blowby gases to the engine air-fuel intake system rather than discharge them into the atmosphere.

As a part of a va'stsmog reduction program, considerable effort is being made in the automotive industry to develop satisfactory devices for destroying harmful crankcase emissions by recirculating them through the engine cylinders. Such recirculation of crankcase emissions upsets the air-fuel ratio established by the engines carburetion system and creates a major problem to be overcome in the design of this type of crankcase ventilation system. The problem is complicated, of course, by the fact that the amount of crankcase emissions varies widely over the operating range of an engine.

The present invention provides a remarkably simple solution to this problem by means of an arrangement in which the crankcase gases are divided to fiow in parallel to two different points in the engine air-fuel intake system. These points and flows are selected so that an enriching effect produced by one flow is automatically compensated by a leaning etfect produced by the other with the result that the air-fuel ratio of the mixture reaching the cylinders is within a range that gives satisfactory. performance. The invention may be easily installed as original equip ment or as an accessory and does not require any change in an engines ventilation air flow rate or in carburetor 'ets; and it eliminates the crankcase emissions without an increase in harmful constituents in the engine exhaust gases.

Therefore, a principal object of the present invention is to provide a crankcase ventilating system incorporating air-fuel ratio control means for maintaining a substantially constant air-fuel ratio despite the complete venting of crankcase gases into the engine air-fuel intake system.

Another object is to provide air-fuel ratio change compensating means for controlling changes in air-fuel ratio caused by venting crankcase gases into the engine air-fuel intake which utilizes normal crankcase ventilation air to compensate forupstream blow-by enrichment and which is responsive to engine operating conditions to provide compensation over a Wide range of engine operating conditions. t

A further object is to provide air-fuel ratio change compensating means in a crankcase ventilating system which is integrally associatedwith the system components and requires no changes in carburetor design or in design of other engine components.

It is a particular object of the invention to provide a crankcase ventilating system wherein crankcase gases are vented to the engine air-fuel intake system, which may be readily installed on used vehicles.

Another object of the present invention is to provide a kit-type engine ventilating system especially adapted for use on used vehicles and comprising only a specially designed air inlet means communicating with the interior of the engine and a ventilating hose assembly adapted to be connected at one end to the engine interior and at the other end at specified locations above the carburetor and below the engine throttle valve.

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A further object of the present invention is to provide an engine ventilating system having a compensating flow passage with an orifice to control the rate of flow and having an orifice cleaning device integrally associated therewith.

Still another object of the present invention is toprovide new and improved means to clean a control orifice associated with an engine ventilating system;

An additional object is to provide a new and improved flame trap means in combination with a hose assembly for connecting the interior of an engine with a source of low pressure to induce a ventilating flow of gases from the engine interior.

The aforementioned objects, and others, are attainable by utilization of the inventive principles hereinafter described in detail by reference to an illustrative embodiment of the invention shown in the accompanying drawings wherein:

FEGURE 1 is a side elevational view, partly in section and schematic, of the illustrative embodiment of the invention;

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1;

PEG. 3 is an exploded perspective view, partly broken away, of theapparatus shown in FIG. 1; and

FIG. 4 is a perspective view of an alternative embodiment of a portion or" the apparatus shown in FIG. 1.

Referring now to PEG. 1, the present engine ventilating system is shown in associationwith a typical internal combustion engine it; having an air-fuel intake system comprising a manifold passage 12, a carburetion device 14 provided with a throttlevalve 16, and an air cleaner assembly 1%. The engine components, per se, for-m no part of the present invention and the inventive principles are equally applicable to various engine designs. The air cleaner assembly may be of various designs but, as illustrated, includes a replaceable filter unit 20, preferably made from foam plastic material such as polyurethane. The oil filler tube 21 is provided with a specially designed filler tube cap 22 incorporating a check valve which replaces the conventional cap. It has an air inlet passage 24 and filter means 26 for supplying the. interior of the engine with clean filtered air for ventilation. A one-way valve 2'7 is associated with the cap to prevent'back flow and escape of crankcase gases to the atmosphere through the filler tube. While the invention requires ventilation air flow into the crankcase, it is independentof the rate of such flow and the cap 22 is therefore preferably de signed to give the normal flow rate that would be used in the engine were the invention not associated with it. i

The ventilationilow passages are provided by a flexible hose assembly 39 which is adapted for attachment to any of the many varieties of internal combustion engines with a minimum of assembly operations, adjustments, and

expense. The hose components are made from a suitable grade of neoprene or the like which will be resistant to all the contaminants likely to be in contact therewith either interiorly or exteriorly.

The hose assembly 39 comprises a main ventilating hose 32 that can be connected at one end 34 to an engine outlet passage 36 communicating with the. engine interior including the crankcase 35. An enlargedreinforcement 37 may be integrally formed on the end of the hose or, as an flternate embodiment, stapled thereto. The outlet 36 may be provided in most instances by the conventional road draft tube of the engine. The outer diameter of the tube and the inner diameter of the hose are approiiimately equal so that a simple ring-type fastener 33 may be used to secure the hose in telescoped relationship on the tube. The upper end 40 of the main hose 32 may be connected at 42 to the air cleaner 18 through an aperture 44 provided in the side wall 46 of the cleaner. The aperture may be otherwise located as, for example, at 47 in the bottom plate on the downstream side of the filter The apertures 44 and 47 may be formed at the assembly of the present ventilating system or may be integrally formed beforehand during manufacture of the air cleaner. The diameter of the aperture is approximately equal to or slightly smaller than the outer diameter of the end of ho se 32 to obtain an air-tight connection. The connection is accomplished by resilient compression of a plurality of convolutions 48 on the end of the hose and insertion of the compressed end of the hose into the opening 44. The convolutions on the end of the hose may be integrally formed on the main hose 32 or, as an alternate embodiment, may comprise a separate member 50 stapled thereto. When the end of the hose and some of the convolutions have been located within the aperture 44, the

hose is released for expansion to the normal cylindrical form to attain an air-tight seal between adjacent convolutions, the outer periphery of the hose, and the edges of the aperture.

The main hose 32 provides an upstream system in that the ventilating passage discharges crankcase gases upstream of the main jet (not shown) of the carburetor 14 and the effect of these is to enrich the carbureted rnixture flowing into the manifold. In order to compensate for this change in air-fuel ratio, the hose assembly 30 includes an air-fuel ratio change compensating means in the form of a branch passage hose (preferably of short length) that is connected to the main hose 32 at one end 62 by a ring-type clamp 64 and a special fitting 65. The other end 66 is connected to an inlet tube 68, communicating with the engine manifold passage 12, by a fastening ring 70. The inside diameter of branch hose 60 is approximately equal to or slightly smaller than the outside diameter of the tube 68.

Referring now to FIG. 2, the special fitting comprises an integrally associated orifice means and orifice cleaner means. The connection between the hose 32 and the hose 60 is made by a connecting assembly comprising a tube element 76 having a length substantially longer than the diameter of hose 32 and an outer diameter substantially equal to the inner diameter of the branch hose 60. The tube 76 is divided into a relatively short portion 78 and a relatively long portion 80 by cen trally located cutouts 82, 84 which define relatively narrow connecting ribs 86, 87 between the short portion and the long portion. The cutouts form inlet ports communicating with the hose 32 so that a flow of gases may be established from hose 32 to hose 60. A pair of oppositely aligned bores 88, 90 having diameters substantial- 1y equal to or slightly less than the outer diameter of the tube member 76 are formed in the main hose 32. An end cap 94 is fixedly secured in the outer end of the shorter portion 78 of the tube 76 and comprises a radial outwardly extending flange portion 96 and a cylindrical portion 98 having a length approximately equal to the length of the short portion 78. The end of the cylindrical portion 98 opposite the flange portion 96 terminates in a radially inwardly extending end wall 99. Shaft guide and bearing means are found in the end cap by a bore 100 in the end wall and a radially inwardly extending rib 102 formed in the cylindrical portion 98 at a spaced location relative to the bore 100. The rib 162 also serves to secure the end cap within the tube 76 by means of a cooperating rib 104. The ribs may be formed by crimping during assembly.

An orifice thimble or plug is fixedly secured in the elongated portion 80 of the tube member 76 by crimping the outer periphery of the tube portion 80 as indicated at 112 to form inwardly displaced rib portions 114, 116. The orifice thimble comprises a cylindrical body provided with a radially inwardly curved cap portion 117 having a (F; centrally located orifice 118 formed therein. The orifice 118 controls the rate of flow of ventilating gases from the engine into the manifold passage 12 and is sized in a particular manner to be hereinafter described in detail.

The blowby gases contain noxious matter which tends to collect around and possibly close the orifice 118. Consequently, we have found it desirable to provide means to keep the orifice clear. In the illustrative embodiment, an orifice cleaning means 122 is integrally associated with the fitting 65 and comprises a plunger shaft 123 having an actuating button 124 formed on one end thereof. The plunger shaft 123 is adapted to be slidably and rotatably supported and retained within the tube 76 by the bearing means formed in the end cap 94. The plunger is rotatably and slidably supported by the peripheries of the bore 100 and the inwardly displaced rib 102. In order to prevent removal of the plunger, portions 126, 127 of the shaft are radially distended to provide a retaining abutment means adapted to engage the side surface of the flange portion 100. A compression spring 128 is mounted circumjacent the plunger shaft 123 and is seated at one end 130 of the button 124 and at the other end 132 on the flange 96 of the end cap 94. The ears 126 and 127 are thereby seated against the flange 109. The end 133 of shaft 123 is formed so that it can be projected into the orifice 118 for cleaning thereof by axial and/ or rotational movements relative thereto. The external plunger 122 makes it easy to keep the orifice 118 clean and of the desired size. For example, every time the oil is checked the plunger could be pushed in to clear the orifice.

In order to provide resistance to reverse flow in the upper end of the main pasasge 32 and to prevent a backfire or the like from emitting flames into the ventilating system, a combination restrictor and flametrap is secured in the end 40 of the main hose 32 adjacent the air cleaner inlet 44. The restrictor and flame trap comprises a wad of aluminum wire mesh material, such as a brush-like member 141 having a central rod portion 142 and radially extending members 143, or the like, which is stuffed into the end of the hose and secured in place therein by means of a clip 144, or the like. As may be seen in FIG. 3 the clip comprises a substantially semicylindrical portion 145 and a flat diametrical portion 146. An additional flame trap member 147, of similar design, may be provided at the inlet end of the main pasasge 32 as shown in FIG. 1. Thus, it may be seen that the main pasage 32 is continuous, uninterrupted, and constantly and permanently open to flow of blowby during normal crankcase ventilation operation. Similarly, the branch pasasge 60 is also continuous, uninterrupted, and constantly and permanently open to flow of blowby during normal crankcase ventilation operation. It will, of course, be understood that the afore described condition pertains during normal operation and does not preclude temporary closing of the passages such as when the orifice cleaner is operated.

The subject ventilating system is adapted for association with a conventional internal combustion engine by changing the original equipment filler tube cap to the valved filler tube cap 22. In addition, an aperture 44 (or 47) having a diameter slightly smaller than the outer diameter of the main hose 32 is cut into a wall of the air cleaner 18. The end 40 of the main hose may then be connected to the air cleaner by compression of the end of the hose and insertion of some of the convolutoins 42 into the air cleaner aperture 44. When the convolutions have been inserted, the compressed end portion is released and the hose returned to the normal cylindrical configuration to cause sealing engagement of the outer periphery of the hose with the edges of the aperture 44. The other end 34 of the main hose is mounted on a suitable outlet tube 36 communicating with the interior of the engine 10. The outer diameter of .the tube may be made substantially the same as the inner diameter of the hose 32 so that the end of the hose may be slidably mounted over the inlet tube. A conventional clamp 38 is then mounted over the hose to secure it permanently in sealed engagement on the tube. The branch hose 60 is similarly mounted on the inlet tube 68 and the hoses may be supported as necessary by clips or the like, secured to the engine or surrounding structure.

.The branch hose may be preassembled on the main hose or the assembly may be made when the hoses are attached to the engine. The main hose is provided with a centrally located cross bore represented by the oppositely aligned apertures 83, 9i). The tube 76 is preferably made with an outer diameter slightly larger than the diameter of the bores of the passages 88, 9d and the tube is inserted into the bores and pushed through the hose. The connecting bars 86, 87 of the tube are substantially equal to the width of shaft 123 and are preferably aligned with the direction of flow of the ventilating gases when the assembly is properly located in the main tube 32. Therefore, a minimum restriction to flow through the hose 32 is provided by the central section of the tube '76 having a width equal only to the width of the shaft 123. The tube '76 is inserted through the bores until the retaining flange 96 is located in abutting engagement with the side wall of the main hose 32 adjacent the aperture 88. The tube 76 has a length sufficient to provide an extended length 3&3 of the tube protruding outwardly through the opposite bore 90. One end 62 of the branch hose 60 is slidably mounted over the end of the tube portion 81 The diameter of the branch hose is apporximately equal to the outer diameter of the tube '76 and conventional clamp 6 5 may be used to sealingly engage and secure the branch hose in place on the tube. The tube 75 has the centrally located orifice 113 which controls the flow of gases from the interior of the engine through the branch passage 60 to the manifold 12.

Crankcase gases entering the main hose 32 comprise principally carhureted blow-by at the normal air-fuel ratio that goes by the piston rings on the compression stroke and air drawn in through cap 22 along with some relatively small amount of miscellaneous non-combustible constituents such as oil or water vapors.

fuel ratio inasmuch as fuel is drawn from the carburetor as if there was 100% air intake, whereas there is actually some previously carbureted blow-by and non-combustibles in the crankcase gases that are mixed with the normal intake air. Thus, as compared with the normal air-fuel ratio for the engine, there is a rich mixture flowing by the throttle valve 16 and a lean mixture entering at inlet 68 from branch hose 60 when the present system is installed on the engine. It is the purpose of the present invention to utilize the lean mixture in branch 6t) to compensate for the enrichment caused by flow from the main hose section and produce a resutling air-fuel ratio that is within acceptable limits. Such limits have been determined to be generally 1% enrichment and 4% leaning of the normal air-fuel ratio for the engine in question. Thus, the rate of flow of gases through branch is critical if the proper compenastion is to be achieved so as to confine the changes in air-fuel ratio within the 1% rich and 4% lean limits. We have discovered that .if the compensation flow rates through branch passage 60 are set substantially as specified in Table I for the various engines, the air-fuel ratio changes will be controlled within the desired limits mentioned above.

1 Intake manifold (downstream of throttle valve).

It can be shown somewhat more generally that the How rate required in branch 60 for satisfactory compensation can be determined by consideration of the formula:

Where A=change in the air-fuel ratio B iiow rate of carbureted blow-by plus air in branch 60 C- rate of carbureted blow-by flow past-the pistons D normal rate of intake air flow into carburetor Items C and D are factors which are known or can be measured for an engine. Perfect compensation occurs if the flow rate in branch 6ft is such that A=O. However, satisfactory performance is obtained if A is 1% minus (enrichment) or 4% plus (leaning). Therefore, the required iiow in branch at can be determined.

While various factors affect the flow rate of branch 66, such as hose material, diameter and length, we prefer to select the proper size of orifice 11$ to obtain the flow rates shown in Table I. This enables all components of system 30 to be standardized for substantially all vehicles except the orifice sizes which can be individually determined for each vehicle class to give the specified compensation flow rates.

It will now be realized that the invention provides a relatively simple and inexpensive means for eliminating crankcase emissions which does not harmfully upset the air-fuel ratio because of its automatic compensation feature. Furthermore, the system does this without increasing the total ventilation flow or introducing other undesirable side effects. Modifications may be made in the structure shown without departing from the spirit and scope of the invention.

What is claimed is: i

1. In an engine ventilating system for an engine having an air-fuel intake system including a carburetor and a throttle valve, a main ventilating passage formed by a flexible hose, one end of said flexible hose: communicating with the interior of said engine, the other end of said flexible hose communicating with the air intake system of said engine upstream ofthe throttle valve, a transverse bore formed in said flexible hose by opposite aligned openings in the side walls thereof, and branch passage means connccted'through said bore at one end to said main passage and connected at the other end to the airfuel intake system of said engine downstream of the throttle valve.

2. The invention as defined in claim 1 and having coupling. means. mounted in said transverse bore, passage means formed in said coupling means and connecting said branch passage means to .said main passage means. i i

3. The invention as defined in claim 2 and wherein orifice means are mounted in said passage means to control the rate of flow of gases therethrough.

4. The invention as defined in claim 3 and wherein an orifice cleaning means is integrally mounted on said coupling means.

5. The invention as defined in claim 4 and wherein said orifice cleaning means comprises a plunger mounted for axial and rotational movement in said passage means, and scraping means mounted on the end of said cleaning means for axial insertion into said orifice and rotation therewithin.

6. The invention as defined in claim 5 and wherein bearing means are mounted in said passage means to slidably and rotatably support said plunger, said bearing means comp-rising axially spaced radially inwardly extending walls defining rims engageable with said plunger, and abutment means formed on said plunger on opposite sides of said bearing means to prevent withdrawal of said plunger.

7. The invention as defined in claim 2 and wherein said coupling means comprises a T-shaped coupling extending through said opposite aligned openings and having a flange portion at one end in sealing engagement with one side surface of said flexible hose, the other end of said coupling extending beyond said flexible hose and said branch passage means being mounted on the other end of said T-shaped coupling.

8. The invention as defined in claim 7 and wherein said T-shaped coupling is provided with a control ori- 9. The invention as defined in claim 8 and wherein said T-shaped coupling is provided with orifice cleaning means.

10. The invention as defined in claim 9 and wherein said orifice cleaning means comprises a plunger member slidably carried internally of said T-shaped coupling, and said plunger means having a conical surface provided on one end and being movable into cleaning engagement with said orifice by axial movement of said plunger.

11. A ventilating system for an internal combustion engine having an air-fuel intake system including a carburetor and a throttle valve, a main hose to be connected at one end to the interior of the engine and to be connected at the other end to the air intake system upstream of the carburetor, a branch hose communicating at one end with the main hose and at the other end adapted to be connected with the air-fuel intake system downstream of the throttle valve, coupling means to connect said branch hose to said main hose and comprising tube means, a transverse bore formed in said main hose and extending through opposite side wall portions thereof and adapted to receive said tube means, one end of said tube means extending a substantial distance outwardly beyond said main hose means to receive said branch hose in telescopic relationship, the other end of said tube means having a shoulder for engagement with the side wall of said main hose, internal passage means provided in said tube means and communicating with the interior of said main hose means, and fastening means to secure said branch hose to said tube means.

12. The invention as defined in claim 11 and wherein said tube means is provided with an orifice in said intern-a1 passage means.

13. The invention as defined in claim 12 and wherein said tube means is further provided with plunger means to clean said orifice.

14. The invention as defined in claim 12 and wherein 'said orifice comprises an orifice thimble, said orifice thimble being fixedly secured in said tube means and having a curved cap surface, said orifice being formed in said curved cap surface.

15. The invention as defined in claim 13 and wherein said plunger means comprises a T-shaped member having a conical point at one end and a control button at the other end, a compression spring mounted about said plunger and being supported at one end against the side wall of said main hose and at the other end against the control button portion to enable said plunger to be axially displaced against the bias of the compression spring to locate said conical point in said orifice for cleaning thereof, and abutment means formed on said plunger interiorly of said tube means to prevent removal of said plunger from within said tube means.

16. In an engine ventilating system for an engine having an air-fuel intake system and a crankcase, including a carburetor and a throttle valve, first ventilating passage means for establishing a flow of blowby from the crankcase to the air-fuel intake system above the throttle valve, said first ventilating passage means providing a free flow passage permanently open to flow in either direction throughout its length, a second ventilating passage means connected to said first ventilating passage means between said crankcase and the air-fuel intake system and to the air-fuel intake system below the throttle vale, ventilating air inlet means connected to said crankcase to provide a source of fresh air, and air-fuel ratio change compensating means associated with said second ventilating passage means to provide a predetermined maximum flow rate of gases from the crankcase through said second ventilating passage means and to divert those portions of gas flow above said maximum flow rate to said first ventilating passage means to maintain the air-fuel ratio within predetermined limits.

17. The invention as defined in claim 16 and wherein said air-fuel ratio change compensating means comprises an orifice mounted in said second ventilating passage means.

18. The invention as defined in claim 17 and wherein an orifice cleaner means is integrally associated with said orifice in said second ventilating passage means.

19. The invention as defined in claim 16 and wherein said first ventilating passage means comprises a main hose, said second ventilating passage means comprising a branch hose, and connecting means connecting said branch hose to said main hose intermediate the ends thereof.

20. The invention as defined in claim 19 and wherein said main hose has an internal diameter larger than said branch hose, one end of said connecting means extending within said main hose through the side wall thereof and the other end of said connected means communicating with said branch hose.

21. The invention as defined in claim 20 and wherein said air-fuel ratio change compensating means comprises an orifice controlling flow into said branch hose from said main hose.

22. The invention as defined in claim 21 and wherein said orifice is integrally associated with said connecting means.

23. The invention as defined in claim 22 and wherein an orifice cleaner means is integrally associated with said orifice.

24. In an engine ventilating system having a main ventilating passage and a branch ventilating passage, a coupling member for connecting said main ventilating passage and said branch ventilating passage comprising a tube member, portions of said tube member being cutout to divide said tube member into a relatively short portion and a relatively long portion, an orifice thimble mounted in said long portion and being crimped in place therein, an orifice centrally located in said orifice thimble, an end cap mounted in the short portion of said sleeve and including a flange, said end cap being crimped within said short portion with said flange extending radially outwardly beyond said tube member to provide an abutment surface, spaced shaft-supporting means integrally formed in said end cap, an orifice cleaning plunger having a shaft portion slidably and rotatably supported by said shaft supporting means for movement to and from contacting engagement with said orifice for cleaning thereof by axial and rotational movement relative thereto, and

9 fastening means supporting said cleaning plunger in said tube member.

25. A method of ventilating an internal combustion engine comprising the steps of establishing a ventilating flow of crankcase gases from .the crankcase to the airfuel intake systemthrough a main passage having an outlet to said air-fuel intake system upstream of the carburetor, separating flow of crankcase gases in said main passage and delivering a portion of said crankcase gases to another passage having an outlet to said air-fuel intake system downstream of the throttle valve, maintaining said main passage and the other passage continuously open to flow from end to end, and controlling the rate of flow of crankcase gases through the other passage in accordance with engine operating conditions to maintain the change in air-fuel ratio caused by introduction of the crankcase gases into the air-fuel intake system between 1% enriched and 4% lean.

26. A method of ventilating an internal combustion engine comprising the steps of establishing a ventilating flow of crankcase gases including ventilation air from the crankcase to the air-fuel intake system through a main passage having an outlet to said air-fuel intake system upstream of the carburetor, diverting the flow in said main passage to another passage having an outlet downstream 4 erating conditions to maintain the change in air-fuel ratio caused by introduction of the crankcase gases into the airfuel intake system within a range of flow rates having a minimum flow rate of approximately 0.70 c.f.m. and a maximum flow rate of approximately 3.00 c.f.m. with said limits being variable within said range depending upon engine displacement.

27. A crankcase ventilating system for an internal combustion engine having an air-fuel intake system and fuel supply means to obtain a particular air-fuel ratio, comprising: crankcase ventilating air inlet means, ventilating air-blowby outlet means in the crankcase for establishing flow of a ventilating air-blowby mixture from the crankcase, first constantly open passage means connecting the ventilating air-blowby outlet means and the airfuel intake system above the fuel supply means to deliver a ventilating air-blowby mixture from the crankcase to the air-fuel intake system at a location causing enrichment of the air-fuel ratio in said air-fuel intake system,

second constantly open passage means connecting the ventilating air-blowby outlet means and said air-fuel intake system below the fuel supply means to supply a ventilating air-blowby mixture from the crankcase to the air-fuel intake system at a location causing leaning of the air-fuel ratio in the air-fuel intake system, and air-fuel ratio change control means in said passage means for controlling the air-fuel ratio changes caused by the introduction of the ventilating air-blowby mixture into the air-fuel intake system, said air-fuel ratio change control means adapted to distribute the flow of the ventilating air-blowby mixture between said first passage means and said second passage means whereby the enrichment effect of the ventilating air-blowby mixture delivered to the airfuel intake system above the fuel supply means through said first passage means and causing enrichment of the air-fuel ratio offsets the leaning effect of the ventilating air-blowby mixture delivered to the air-fuel intake system below the fuel supply means through said second passage means to maintain the air-fuel ratio changes within predetermined limits.

28. In an engine ventilating system for connection to an engine having an air-fuel intake system with fuel supply means, a first permanently open crankcase ventilating passage means, means connecting one end of said first permanently open crankcase ventilating passage means to the interior of the engine, means connecting the other end of said first permanently open crankcase ventilating passage means to the air-fuel intake system upstream of said fuel supply means, a second permanently open crankcase ventilating passage means, means connecting one end of said, second permanently open crankcase ventilating passage means to said first permanently open crankcase ventilating passage means intermediate the ends of said first permanently open crankcase ventilating passage means, means connecting the other end of said second permanently open crankcase ventilating passage means to the air-fuel intake system downstream of said fuel supply means, and means to limit flow of blowby from said engine to said air-fuel intake system through said second ventilating passage means during all conditions of engine operation to a predetermined maximum fiow and to divert flow of blowby from the crankcase above the predetermined maximum limit imposed in said second permanently open Ventilating passage means to said first permanently open crankcase ventilating passage means for delivery to said air intake system upstream of the fuel supply means whereby, a predetermined portion of the blowby is delivered to the intake system downstream of the fuel supply means at a location causing leaning of the air-fuel ratio and the rest of the blowby is delivered to the air-fuel intake system upstream of the fuel supply means at a location causing enrichment of the air-fuel ratio, the leaning and enrichment effects of the blowby on the air-fuel ratio each compensating for changes in the air-fuel ratio caused by the other.

29. The invention as defined in claim 28 and wherein said first permanently opened crankcase ventilating passage means comprises a main flexible ventilating hose extending between the interior of said engine and said air intake system upstream of the throttle valve and said second permanently open crankcase ventilating passage means comprises a flexible branch ventilating hose connected to the main ventilating hose intermediate its ends and to the air intake system downstream of the throttle valve.

30. In a crankcase ventilation system, connecting means for separate crankcase ventilation passage means, orifice means in said connecting means to control flow of blowby through said passage means, and manually operable cleaner means in said connecting means to clean said orifice means.

31. In a crankcase ventilating system, a coupling for connecting crankcase ventilating hoses comprising internal passage means, orifice means mounted in said passage means to control the rate of flow of blowby therethrough, orifice cleaning means comprising a plunger mounted for axial movement in said passage means, and scraping means mounted on the end of said cleaning means for axial insertion into said orifice means.

32. A coupling for connecting crankcase ventilating hoses comprising internal passage means, orifice means mounted in said passage means to control the rate of flow of gases therethrough, orifice cleaning means comprising a plunger mounted for axial movement in said passage means, bearing means mounted in said passage means to slidably support said plunger, said bearing means comprising radially inwardly extending walls defining rim means engageable with said plunger, abutment means formed on said plunger on opposite sides of said bearing means to prevent withdrawal of said plunger, and scraping means mounted on the end of said cleaning means for axial insertion into said orifice means.

33. A crankcase ventilating system for an internal com bustion engine having a crankcase and an air-fuel intake system comprising a single continuous and uninterrupted ventilating passage means connecting the crankcase to the air fuel intake system to establish a first blowby flow path to the air-fuel intake system, a second continuous and uninterrupted passage means connecting said single continuous and uninterrupted ventilating passage means to the air-fuel intake system to establish a second blowby 1 1 flow path to the air-fuel intake system, and means in said second continuous and uninterrupted passage means for establishing flow of blowby from the crankcase in the two flow paths, one of said flow paths being adapted to continuously handle a predtermined maximum flow and the other of said flow paths being adapted to handle excess flow above said predetermined maximum flow, said last mentioned means being calibrated to establish a maximum flow such as to maintain the changes in the air-fuel ratio caused by delivery of blowby to the air-fuel intake system between predetermined limits.

34. In an engine ventilating system for an engine having an air fuel intake system including a carburetor and a throttle valve, a first ventilating passage connected at one end with the interior of said engine and connected at the other end with the air intake system of said engine upstream of said throttle valve, a second ventilating pausage connected at one end to said first ventilating passage and connected at the other end to the air fuel intake system of said engine downstream of the throttle valve, orifice means mounted in said second ventilating passage, and flame arrestor means mounted in said first ventilating passage between the other end of said first ventilating passage and the one end of said second ventilating passage.

35. The invention as defined in claim 34 and wherein said flame arrestor means is mounted closely adjacent said other end of said first ventilating passage to provide resistance to reverse flow of fluids in said first ventilating passage from said air intake system to said second ventilating passage.

36. The invention as defined in claim 35 and wherein said first ventilating passage is formed by flexible hose means, said flame arrestor means comprising a resiliently compressible material, and means for securing said flame arrestor means in said resilient hose means by resilient deflection of said flame arrestor means.

References Cited in the file of this patent UNITED STATES PATENTS 1,795,245 Bichler Mar. 3, 1931 2,056,762 Barr Oct. 6, 1936 2,281,124 Westcott Apr. 28, 1942 2,489,230 Winkler Nov. 22, 1949 2,493,617 Chubbuck Jan. 3, 1950 2,633,113 McCarty Mar. 31, 1953 3,056,420 Dietrich Oct. 2, 1962 

1. IN AN ENGINE VENTILATING SYSTEM FOR AN ENGINE HAVING AN AIR-FUEL INTAKE SYSTEM INCLUDING A CARBURETOR AND A THROTTLE VALVE, A MAIN VENTILATING PASSAGE FORMED BY A FLEXIBLE HOSE, ONE END OF SAID FLEXIBLE HOSE COMMUNICATING WITH THE INTERIOR OF SAID ENGINE, THE OTHER END OF SAID FLEXIBLE HOSE COMMUNICATING WITH THE AIR INTAKE SYSTEM OF SAID ENGINE UPSTREAM OF THE THROTTLE VALVE, A TRANSVERSE BORE FORMED IN SAID FLEXIBLE HOSE BY OPPOSITE ALIGNED OPENINGS IN THE SIDE WALLS THEREOF, AND BRANCH PASSAGE MEANS CONNECTED THROUGH SAID BORE AT ONE END TO SAID MAIN PASSAGE AND CONNECTED AT THE OTHER END OF THE AIRFUEL INTAKE SYSTEM OF SAID ENGINE DONWSTREAM OF THR THROTTLE VALVE. 